The present invention relates to apparatus for forming and moving a yarn reserve in an open-end spinning machine.
Apparatus of the type to which the invention is directed include a spinning turbine or a plurality of parallel-connected spinning turbines and yarn exit openings which are provided with oppositely arranged pairs of delivery rollers. The exit openings are connected in series with a yarn guide rod provided with guide elements and displaceable in a direction transverse to the axis defined by the exit opening and its associated delivery roller pair, the rod forming a deflection device which carries along the yarn coming out of the exit opening.
Spinning turbine machines require an apparatus for forming a yarn reserve because the machine can be restarted only if a yarn reserve can be refed into the spinning turbine within fractions of seconds in order to be connected in the fiber collection trough of the spinning turbine to the ring of fibers formed of fibers just previously fed thereinto.
It is furthermore the custom to displace the yarn coming from the exit opening of the spinning turbine from side to side by a few millimeters. This back-and-forth movement of the yarn prevents the formation of tracks, or grooves in the rubber coating of the pressure roller of the associated pair of discharge rollers.
East German Pat. No. 82,078 describes an apparatus for open-end spinning machines for returning the yarn end into the spinning member during restarting of spinning in which the finished yarn is removed by means of delivery rollers and is wound on a spool. The spinning chamber is followed by a stationary yarn guide, while a further stationary yarn guide is provided in front of the spool. A movable yarn guide is disposed in the region of the delivery rollers between the spinning chamber and the discharge rollers and this yarn guide is movable in the axial direction of the delivery rollers and is provided with a slit as the guide element.
The yarn guide is provided, in addition to the drive for forming and releasing the yarn reserve loop, with a second drive for a back-and-forth movement of the yarn between and transversely of the delivery rollers, both drives being elastically coupled together. While the back-and-forth movement is produced by a motor and a rope pulley disposed on a crank, the reserve force required for the formation of the yarn reserve loop is effected by a magnet.
The drawback of this known apparatus is that the reserve force for the yarn guide is produced by magnets which suddenly move the pulling means which is in connection with the yarn guide. However, the formation of the yarn reserve loop must be effected very slowly since otherwise the yarn could be pulled out of the spinning turbine and may break.